1. Field of the Invention
This invention relates to improvements in lightning conductors.
2. Description of the Prior Art
It is generally agreed that Benjamin Franklin invented the conventional lightning conductor. Prior to 1752 he and three friends showed, through experiments, that electricity was attracted to sharpened pieces of metal. In 1753 Franklin wrote a detailed description of a lightning conductor. Since that time conductors in the nature of sharp pointed rods, located on the top of structures, to capture lightning discharges, have been commonly known as Franklin rods.
Since Franklin first described his concept of lightning protection, there have been a number of perceived improvements to Franklin rods. They may be summarised as follows:
1. Multiples points fanning out from a single rod.
2. Radioactive emissions to enhance air conductivity around the point.
3. A solar or battery powered spark generator to create ionization.
4. Spark generators which derive energy from the natural electric field which exists during a thunderstorm and preceding a lightning stroke.
In U.S. Pat. No. 4,540,844 to Sautereau et al, there is described a single-point Franklin rod which is brought to a high tension potential by a generator to produce and maintain at its maximum a corona discharge. The ions generated by the corona discharge form a column of ionized air above the point of the rod, to facilitate the occurrence of lightning by increasing the conductivity of the atmospheric air.
U.S. Pat. No. 4,518,816 to Robert discloses a lightning conductor which uses a piezoelectric device to create a corona effect and atmospheric ionization.
In U.S. Pat. No. 4,565,900, there is disclosed a single-point rod connected to an accelerator consisting of radially arranged metal deflector plates and needles on a dielectric plate in register with apertures in the metal plate. The rod and plates are positively charged and the needles are negatively charged, the resulting electric field creating ionization.